Effectiveness and safety of anti-tau drugs for Alzheimer's disease: Systematic review and meta-analysis

Controversial Past, Splendid Present, Unpredictable Future: A Brief Review of Alzheimer Disease History

Background: The concept of Alzheimer disease (AD)-since its histological discovery by Alzheimer to the present day-has undergone substantial modifications. Methods: We conducted a classical narrative review of this field with a bibliography selection (giving preference to Medline best match). Results: The following subjects are reviewed and discussed: Alzheimer's discovery, Kraepelin's creation of a new disease that was a rare condition until the 1970's, the growing interest and investment in AD as a major killer in a society with a large elderly population in the second half of the 20th century, the consolidation of the AD clinicopathological model, and the modern AD nosology based on the dominant amyloid hypothesis among many others. In the 21st century, the development of AD biomarkers has supported a novel biological definition of AD, although the proposed therapies have failed to cure this disease. The incidence of dementia/AD has shown a decrease in affluent countries (possibly due to control of risk factors), and mixed dementia has been established as the most frequent etiology in the oldest old. Conclusions: The current concept of AD lacks unanimity. Many hypotheses attempt to explain its complex physiopathology entwined with aging, and the dominant amyloid cascade has yielded poor therapeutic results. The reduction in the incidence of dementia/AD appears promising but it should be confirmed in the future. A reevaluation of the AD concept is also necessary.

Synthetic Thioesters of Thiamine: Promising Tools for Slowing Progression of Neurodegenerative Diseases

Thiamine (vitamin B1) is essential for the brain. This is attributed to the coenzyme role of thiamine diphosphate (ThDP) in glucose and energy metabolism. The synthetic thiamine prodrug, the thioester benfotiamine (BFT), has been extensively studied and has beneficial effects both in rodent models of neurodegeneration and in human clinical studies. BFT has no known adverse effects and improves cognitive outcomes in patients with mild Alzheimer's disease. In cell culture and animal models, BFT has antioxidant and anti-inflammatory properties that seem to be mediated by a mechanism independent of the coenzyme function of ThDP. Recent in vitro studies show that another thiamine thioester, O,S-dibenzoylthiamine (DBT), is even more efficient than BFT, especially with respect to its anti-inflammatory potency, and is effective at lower concentrations. Thiamine thioesters have pleiotropic properties linked to an increase in circulating thiamine concentrations and possibly in hitherto unidentified open thiazole ring derivatives. The identification of the active neuroprotective metabolites and the clarification of their mechanism of action open extremely promising perspectives in the field of neurodegenerative, neurodevelopmental, and psychiatric conditions. The present review aims to summarize existing data on the neuroprotective effects of thiamine thioesters and give a comprehensive account.

Effects of three kinds of anti-amyloid-β drugs on clinical, biomarker, neuroimaging outcomes and safety indexes: A systematic review and meta-analysis of phase II/III clinical trials in Alzheimer's disease

OBJECTIVE

To investigate the effects of the three kinds of anti-amyloid-β (Aβ) drugs on cognitive and other functions, fluid and neuroimaging biomarkers, and safety on patients with Alzheimer's disease (AD), and rank the three kinds of anti-Aβ drugs.

METHODS

We searched Medline, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and AlzForum from inception to January 21, 2023 to include randomized controlled clinical trials. Random effects meta-analyses were performed.

RESULTS

Forty-one clinical trials (20929 participants, 9167 male) were included. Anti-Aβ drugs had significant but relatively low efficacy in preventing cognitive decline (ADAS-Cog SMD -0.07, 95% CI: -0.10 to -0.03, p < 0.001; CDR-SOB -0.05, -0.09 to -0.01, p = 0.017). Instrumental variable meta-analysis and trial sequential analysis confirmed the reliability of the pooled estimation. Beneficial effects were also observed by assessing other cognitive and activity of daily living scales and biomarkers, with acceptable safety of anti-Aβ drugs. Meta-regression demonstrated significant association between higher baseline mini-mental statement examination scores (MMSE) and better cognitive protective effects on cognitive function (ADAS-Cog β: -0.02, -0.05 to 0.00, p = 0.017) and clearance of pathological productions of anti-Aβ drugs. Network meta-analysis ranked the passive immunotherapy drugs to have the best cognitive efficacy, followed by active immunotherapy and small molecule drugs.

CONCLUSION

Anti-Aβ drugs have relatively low efficacy in preventing cognitive decline, and they reduce pathological productions with acceptable safety. Patients with higher baseline MMSE scores benefit more from anti-Aβ drugs. Passive immunotherapy anti-Aβ drugs show relatively better efficacy than active immunotherapy and small molecule anti-Aβ drugs.

Mapping new pharmacological interventions for cognitive function in Alzheimer's disease: a systematic review of randomized clinical trials

Background and Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder, that is, characterized by cognitive decline. To date, there are no effective treatments for AD. Therefore, the objective of this study was to map new perspectives on the effects of pharmacological treatment on cognitive function and the overall psychological state in patients with AD. Methods: Two independent researchers searched for randomized clinical trials (RCTs) exploring new pharmacological approaches related to cognition in Alzheimer's disease in adults from 2018 to 2023 in PubMed, Web of Science, Scopus, and Cochrane Library databases. A total of 17 RCTs were included in this review. Results: The results show that in recent years, new drugs have been tested in patients with Alzheimer's disease, including masitinib, methylphenidate, levetiracetam, Jiannao Yizhi, and Huannao Yicong formulas. Most studies have been conducted in populations with mild to moderate Alzheimer's disease. Conclusion: Although some of the drugs found suggested improvement in cognitive function, the scarcity of available studies highlights the need for further research in this area. Systematic review registration: [www.crd.york.ac.uk/prospero], identifier [CRD42023409986].